Ratchet connector for hypodermic syringe pistons

• US 4,931,043 A
• Filed: 08/08/1988
• Issued: 06/05/1990
• Est. Priority Date: 08/08/1988
• Status: Expired due to Term

• Current Assignee: Abbott Laboratories
• Original Assignee: Sterling Drug, Inc. (GSK plc)
• Inventors: Cooper, Michael E., Ray, Jefferson L.
• Primary Examiner(s): Rosenbaum, C. Fred
• Assistant Examiner(s): CERMAK, ADAM
• Application Number:
  US07/229,394
• Time in Patent Office: 666 Days
• Field of Search: 604/228, 604/233, 604/229, 604/225, 604/224, 604/221, 604/220, 604/219, 604/218, 604/210, 604/209, 604/208, 604/193, 604/155, 604/154, 604/152, 604/151, 604/121, 403/287, 403/292, 403/296, 403/298, 403/299
• US Class Current: 604/228
• CPC Class Codes: A61M 5/31511 Piston or piston-rod constructions, e.g. connection of piston with piston-rod A61M5/5066 takes precedence
• CPC Class Codes: A61M 5/31515 Connection of piston with piston rod

Abstract

A connector for attachment of a plunger to a rubber piston in hypodermic syringe cartridge ampoules comprises a pin having a shank portion with a contiguous screw-threaded post portion and a ratchet head portion sized to rotatably fit within a cavity in said piston which thus prevents overtightening the plunger to the piston thereby obviating jamming of the piston in the bore of the cartridge.

Claims

1. A device for use in a hypodermic injection system which comprises in combination a slidable piston with a hollow recess therein and connector means for attaching a plunger to said piston, said connector means comprising a pin, said pin being disposed within said hollow recess of said piston, said pin having a cylindrical shank portion, a ratchet head portion on one end thereof of larger overall diameter than said shank portion and a screw-threaded post portion on the other end thereof wherein said ratchet head portion has a plurality of ratchet teeth arranged around its periphery.

2. A device according to claim 1 wherein the shank portion of said pin has a shoulder adjacent said screw-threaded post portion.

3. A device according to claim 2 wherein said shoulder comprises a flared portion on the end of said shank portion adjacent said screw-threaded post portion.

4. A device according to claim 1 wherein the ratchet head portion of said pin is equipped with four ratchet teeth.

5. A device for use in a hypodermic injection system which comprises in combination a hollow cylindrical cartridge ampoule, a flexible piston slidable in the bore thereof and connector means for attaching a plunger to said slidable piston, said piston having a hollow recess therein, said connector means comprising a pin being disposed within said hollow recess of said piston and having a cylindrical shank portion, a ratchet head portion on one end thereof of larger overall diameter than said shank portion and a screw-threaded post portion on the other end thereof wherein said ratchet head portion has a plurality of ratchet teeth arranged around its periphery.

6. A device according to claim 5 wherein the shank portion of said pin has a shoulder adjacent said screw-threaded post portion.

7. A device according to claim 6 wherein said shoulder comprises a flared portion on the end of said shank portion adjacent said screw-threaded post portion.

8. A device according to claim 5 wherein the head portion of said pin is equipped with four ratchet teeth.